Sandbox: DDx Kidney mass

• 50-60 yo patients
• Flank pain, hematuria
• Birt-Hogg-Dubé syndrome

• Palpable flank mass

• Pale cytoplasm
• Streaks of eosinophilic material
• "Cobwebs" appearance
• Perinuclear clearing
• Psammoma bodies

• Multiple losses of entire chromosomes 1, 2, 6, 10, 13, 17, 21 and Y

Nonmalignant causes

anaplastic sarcoma clear cell sarcoma mesoblastic nephroma metanephric stromal tumor nephroblastomatosis / nephrogenic rests neuroblastoma oncocytoid carcinoma after neuroblastoma ossifying